Cross-counterflow heat exchanger assembly

ABSTRACT

A manifold for use in a heat exchanger assembly and a method of forming the manifold is disclosed herein. The method starts with the step of separately forming a first member at least partially defining an interior and having a spaced set of first tube slots and a second member having a wall positioned against the first tube slots and dividing the interior into a plurality of chambers. The method is finalized with the step of permanently fixing the first member to the second member to define an first manifold after the separately forming step.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to manifolds having multiple passages. More specifically, the invention relates to extruded manifolds with multiple passages and cross-counterflow heat exchangers incorporating such manifolds.

2. Description of the Prior Art

Air-cooling (or heating) cross-counterflow heat exchangers are often used in applications where space limitations restrict the surface area of the heat exchanger. Cross-counterflow heat exchangers typically include a plurality of stacked, assembled modules, with each module including a pair of spaced manifolds interconnected by a plurality of spaced and parallel tubes. The modules are stacked such that air flows in a direction perpendicular to the face of the heat exchanger, and air fins are disposed between adjacent pairs of tubes for transferring heat from the tubes to the passing air.

Another type of cross-counterflow heat exchanger assembly is shown in U.S. Pat. No. 5,941,303, issued to James D. Gowan on Aug. 24, 1998 and hereinafter referred to as Gowan '303. Gowan '303 discloses a cross-counterflow heat exchanger comprising a pair of spaced and continually extruded manifolds. Each of the manifolds includes an interior, and each of the manifolds includes at least one dividing wall to divide the interior into a plurality of flow paths. A plurality of tubes extends and establishes fluid communication between the pair of manifolds. Each of the tubes includes at least one tube divider to separate it into a plurality of passages.

SUMMARY OF THE INVENTION

In summary, the invention provides a manifold for use in a heat exchanger assembly and a method of forming the manifold. The method starts with the step of separately forming a first member at least partially defining an interior and having a spaced set of first tube slots and a second member having a wall positioned against the first tube slots and dividing the interior into a plurality of chambers. The method is finalized with the step of permanently fixing the first member to the second member to define a first manifold after the separately forming step.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a perspective and exploded view of the exemplary embodiment of the invention;

FIG. 2 is a cross-sectional view of the first and second manifolds and the tubes taken along line 2-2 of FIG. 1;

FIG. 3 is a front view of the first member of the exemplary embodiment of the invention;

FIG. 4 is a front view of the second member of the exemplary embodiment of the invention; and

FIG. 5 is a cross-sectional view of one of the tubes taken along line 5-5 of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a heat exchanger assembly 20 is generally shown and includes a first member 22 at least partially defining an interior. Referring to FIG. 3, in the exemplary embodiment, the first member 22 is a channel having a cross-section defining a U-shape and presenting arms 24 integrally connected to a base 26 and extending forwardly to arm ends 28. Referring again to FIG. 1, the base 26 of the first member 22 presents a plurality of first tube slots 30 longitudinally spaced from one another. The first tube slots 30 can be formed by conventional machining methods including stamping, grinding, or milling.

Referring to FIG. 2, the assembly 20 includes a second member 32 comprising a plate 34 and a wall 36 extending transversly to the plate 34. The plate 34 extends between and engages the arm ends 28 of the first member 22 and the wall 36 engages the base 26 of the first member 22 to divide the interior into a plurality of chambers 38, 40. Referring again to FIG. 1, the second member 32 includes a plurality of notches being spaced to correspond with the first tube slots 30 of the first member 22. The second member 32 is permanently fixed to the first member 22 to define an first manifold 42, which is generally indicated. In the exemplary embodiment, the second member 32 is brazed to the first member 22, but any other method of permanently fixing the first and second members 22, 32 may also be used.

Other geometries for the first and second members 22, 32 may be used and are meant to be included in the scope of the invention. For example, the first member may be a flat shield presenting a plurality of first tube slots, and the second member may include a flat plate extending in spaced and parallel relationship with the first member and having a plurality of arms extending transversely therebetween to define an interior divided into a plurality of chambers. The first member may also be cylindrically shaped and present a unified interior defining a plurality of first tube slots. The second member would then be inserted into the first member to divide the unified interior into a plurality of chambers.

The assembly 20 also includes a plurality of tubes 44 extending between first and second tube ends 46, 48. The first tube end 46 of each tube 44 is disposed in one of the first tube slots 30 of the first manifold 42. Referring to FIG. 5, each tube 44 defines at least one tube divider 50 disposed in the tube 44 and extending between the first and second tube ends 46, 48 to define a first passage 52 in fluid communication with one of the chambers 38, 40 and a second passage 54 in fluid communication with the other of the chambers 38, 40. The tube divider 50 at the first tube end 46 abuts and is permanently fixed to the wall 36 of the second member 32.

The assembly 20 further includes a second manifold 56 extending in spaced and parallel relationship with the first manifold 42. The second manifold 56 presents a plurality of second tube slots 58 spaced from each other to correspond with the spacing of the first tube slots 30 of the first manifold 42. The second tube end 48 of each tube 44 extends into and engages the corresponding second tube slot 58 to establish fluid communication between the tubes 44 and the second manifold 56. The second manifold 56 directs the flow of coolant from one of the passages 52, 54 of the tubes 44 to the other to define a two-pass cross-counterflow heat exchanger assembly 20.

In the exemplary embodiment, the tubes 44 and the first and second tube slots 30, 58 each have a cross-section presenting flat sides 60 and round ends. However, the tubes 44 may be have any shape capable of transmitting a fluid between the first and second manifolds 42, 56. The flat sides 60 of adjacent tubes 44 are spaced from one another to define a plurality of air passages for the flow of air therebetween. A corrugated air fin 62 is disposed between and brazed to the parallel flat sides 60 of adjacent tubes 44 and extends between the first and second manifolds 42, 56.

One of the chambers 38, 40 of the first manifold 42 includes an input 64 to define an input chamber 38 for receiving a fluid, and the other of the chambers 38, 40 includes an output 66 to define an output chamber 40 for dispensing the coolant after it has passed through the heat exchanger assembly 20. In the preferred embodiment, the input 64 is disposed on the chamber that is downstream of the direction of the flow of air and the output 66 is disposed on the chamber upstream of the input chamber 38. The input 64 and output 66 may have any shape capable of delivering a fluid to the input and output chambers 38, 40 of the first manifold 42.

The embodiment shown in the drawings is for a two-pass counter cross-flow heat exchanger assembly. However, the manifolds and tubes may be designed to allow for more than two passes by inserting walls in either or both of the first and second manifolds and including a plurality of tube dividers in each tube. For example, in a three-pass heat exchanger assembly, the second member has one wall to divide the first manifold into two chambers, the second manifold has one wall, and each tube has two tube dividers.

The invention also includes a method of forming a first manifold 42 for use in a heat exchanger assembly 20. The method starts with the step of separately forming a first member 22 at least partially defining an interior and a second member 32. The first member 22 has a spaced set of first tube slots 30 and the second member 32 has a wall 36 that is positioned against the first tube slots 30 to divide the interior into a plurality of chambers 38, 40. The method continues with the step of permanently fixing the first member 22 to the second member 32 to define a first manifold 42 after the separately forming step. The second member 32 is preferably extruded and then cut to size, but may also be formed by other methods including casting and machining. In one embodiment, the forming the first member 22 is further defined as rolling a flat sheet of material into a channel having a cross-section presenting a U-shape and having a base 26 and arms 24 extending forwardly to arm ends 28. Rolling the first member 22 from a flat sheet provides advantages because the flat sheet can be a stock sheet of metal with a brazing material pre-disposed on either side of it. The brazing material then may be used for the step of permanently fixing the first member 22 to the second member 32.

The method proceeds with the step of forming a plurality of tubes 44 extending between first and second tube ends 46, 48. The method then continues with the step of forming a tube divider 50 extending between the first and second tube ends 46, 48 in each of the tubes 44 to separate each tube 44 into a first passage 52 and a second passage 54. Referring to FIG. 5, in one embodiment, the forming each tube 44 is further defined by rolling a flat sheet of material into a tube 44 defining a tube divider 50. Rolling each tube 44 from a flat sheet provides advantages because the flat sheet can be a stock sheet of metal having a pre-disposed brazing material on either side of it. The bazing material may then later be used for the step of fixing and sealing the tube ends 46, 48 to the first and second tube slots 30, 58 of the manifolds 42, 56. However, any other method of forming the tube divider 50 may also be used.

The method continues with the step of inserting the first tube end 46 of each tube 44 into one of the first tube slots 30 of the first manifold 42 and abutting the divider of each tube 44 against the wall 36 of the second member 32 to establish fluid communication between the first passage 52 of the tubes 44 and one of the chambers 38, 40 of the first manifold 42 and to establish fluid communication between the second passage 54 of the tubes 44 and the other of the chambers 38, 40 of the first manifold 42. The first tube end 46 of each tube 44 is then permanently fixed to the associated first tube slot 30 first manifold 42.

The method further continues with the step of forming a second manifold 56 having a set of second tube slots 58 being spaced from each other to correspond with the set of first tube slots 30 of the first manifold 42. The method proceeds with the step of inserting the second tube end 48 of each of the tubes 44 into the corresponding second tube slot 58 of the second manifold 56 to establish fluid communication between the first and second passages 52, 54 of each tube 44 and the second manifold 56.

The method is finished with the steps of forming a plurality of air fins 62 and inserting one of the air fins 62 between adjacent tubes 44 to dissipate heat from the tubes 44. In the exemplary embodiment, the tubes 44, manifold, and air fins 62 are all brazed together to define a unified heat exchanger assembly 20.

The subject invention provides for a manifold and a cross-counterflow heat exchanger assembly 20 that is both cheaper and quicker to manufacture than those of the prior art. Many of the traditional methods for forming the tube slots in the first manifold of the Gowan '303 patent must be abandoned in order to avoid interfering with the dividing wall of the first manifold. The first tube slots of the Gowan '303 patent must be milled or grinded, either of which is a very time consuming and costly process. The first tube slots 30 of the present invention may be formed in the first member 22 using a variety of manufacturing methods including stamping before the step of permanently fixing the first and second members 22, 32 together. This leads to significantly greater manufacturing efficiency, thereby reducing the cost and time to assemble the first manifold 42 and of the heat exchanger assembly 20.

While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

1. A method of forming a manifold for use in a heat exchanger assembly including the steps of: separately forming a first member at least partially defining an interior and having a spaced set of first tube slots and a second member having a wall positioned against the first tube slots and dividing the interior into a plurality of chambers; and permanently fixing the first member to the second member to define an first manifold after the separately forming step.
 2. The method as set forth in claim 1 wherein the forming the first member is further defined as rolling a flat sheet of material into a channel having a cross-section presenting a U-shape presenting a base and arms extending forwardly to arm ends.
 3. The method as set forth in claim 1 further including the step of: forming a plurality of tubes extending between first and second tube ends.
 4. The method as set forth in claim 3 wherein the forming each tube is further defined by rolling a flat sheet of material into a tube defining a tube divider.
 5. The method as set forth in claim 3 further including the step of: forming a tube divider extending between the first and second tube ends in each of the tubes to separate each tube into a first passage and a second passage.
 6. The method as set forth in claim 5 further including the step of: inserting the first tube end of each tube into one of the first tube slots of the first manifold and abutting the tube divider of each tube against the wall to establish fluid communication between the first passage of the tubes and one of the chambers of the first manifold and to establish fluid communication between the second passage of the tubes and the other of the chambers of the first manifold.
 7. The method as set forth in claim 6 further including the step of: forming a second manifold having a set of spaced second tube slots to correspond with the set up first tube slots of the first manifold.
 8. The method as set forth in claim 7 further including the step of: inserting the second tube end of each of the tubes into the corresponding second tube slot of the second manifold to establish fluid communication between the first and second passages of each tube and the second manifold.
 9. The method as set forth in claim 8 further including the step of: forming a plurality of air fins.
 10. The method as set forth in claim 9 further including the step of: inserting an air fin between adjacent tubes to dissipate heat from the tubes.
 11. An assembly manufactured according to the method of claim
 1. 12. The assembly as set forth in claim 11 wherein said first member extends longitudinally and said first tube slots are longitudinally spaced from each other.
 13. The assembly as set forth in claim 11 wherein said first member is a channel having a cross-section defining a U-shape and presenting arms integrally connected to a base and extending forwardly to arm ends.
 14. The assembly as set forth in claim 13 wherein said second member includes a plate extending between said arm ends of said channel and said wall extends transversely from said plate to said tube slots of said channel.
 15. The assembly as set forth in claim 11 further comprising: an input disposed on one of said chambers to receive a fluid and to define an input chamber and an output disposed on the other of said chambers to dispense the fluid and to define an output chamber.
 16. The assembly as set forth in claim 11 further comprising: a plurality of tubes extending between first and second tube ends; and said first tube end of each of said tubes is disposed in one of said first tube slots of said first manifold.
 17. The assembly as set forth in claim 16 wherein each of said defines a tube divider extending between said first and second tube to define a first passage in fluid communication with one of said chambers of said first manifold and a second passage in fluid communication with the other of said chambers; and said tube divider at said first tube end abuts said wall of said second member.
 18. The assembly as set forth in claim 17 further comprising: a second manifold extending in spaced and parallel relationship with said first manifold and end engaging said second tube ends of said plurality of tubes to establish fluid communication between said first and second passages of said tubes and said second manifold.
 19. The assembly as set forth in claim 18 wherein said second manifold defines a plurality of second tube slots spaced from each other to correspond with said first tube slots of said first manifold, and said second end of each of said tubes extends into said corresponding second tube slot.
 20. The assembly as set forth in claim 19 wherein each of said tubes has a cross-section defining flat sides and round ends.
 21. The assembly as set forth in claim 20 wherein said flat sides of adjacent tubes are spaced from one another to define a plurality of air passages for the flow of air between said adjacent tubes.
 22. The assembly as set forth in claim 21 further comprising: an air fin disposed between and brazed to said parallel flat sides of said tubes and extending between said first and second manifolds for dissipating heat from said tubes. 